Prop nut coming loose. Idle speed not staying set.

ERock82

Petty Officer 1st Class
Joined
Aug 14, 2014
Messages
230
So here is a post that may be a hard one to answer.

Before I took my boat out last weekend, I had just replaced the powerhead from installing new gaskets. I have done this before with no issues. The main issue I had when all was done was adjusting my idle speed (not carb air mixture). It was way too high. The screw was a little stripped so I replaced and got it somewhere decent.

When I took it out it was jumping real hard from being in gear to going in neutral and from neutral to reverse. Also, the idle would all of a sudden speed up real high when sitting in neutral for a few seconds (Like a ghost was reving it).

I started the boat up several times to observe this and I noticed the carb bowl leaking on the bottom. I had just cleaned it, replaced all the gaskets in it and a new float pin. I was confused....

I readjusted the idle speed screw and whala....the carb was not leaking at all and the motor was acting normal again. I took it out for 30 mins to test. It was making some odd sounds but otherwise ran good. When I returned home, I realized the odd sounds were because the prop nut became completely loose. Funny thing is, I had just tightened the prop real good before going out.

The prop nut came loose the previous time I was out as well but it was just a 5 minute water test that caused that.

I can't figure out why the prop nut would come loose. I can't figure out why the idle speed would change like that and cause carb to leak.

My theory is this: The jumping from gears must have been from the prop being loose. The weird buzzing sounds while cruising must have been from prop loose. Also, maybe the rapid idle speed change caused the carb float pin to stick making carb leak????

If that is correct, that means the prop became loose almost right away, which doesn't make sense.

I want to say the idle speed setting wasn't holding (maybe not tight enough or something wrong there) is causing this but I have no clue. Any help is appreciated. Thanks.
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,924
What we working on(other than a Force)??
The prop nut if it comes loose, then it needs to be replaced.The nylock nut is worn out.
I heard that the nut can be heated(almost melt the plastic) and it might work.
No way your gonna hear the prop buzzing while under way. The thrust hub installed?
The buzzing sound was it an overheat alarm?
 
Top